Process of extracting iron from its ores.



S. G. MARTIN.

PROCESS 0I' EXTRAGTING IRON FROMITS ORES.

APPLICATION FILED JAN. 14. 11109.

Patented Nov. 15, 1910.

UNirnn sini-us Aregular euries.

STEPHEN (LMABTIN, OF CHICAGO, ILLINOIS. ASSIGNOB OF ONE-THIRD T0 WILLIAM 0. BABTHOLOMEW, OF ST. LOUIS, MISSOURI. AND ONE-THIRD T0 EDWARD SCHAAF,

` oF sr. mars, mssounr.

PROCESS 0F EXTRACTING IRON FROM ITS CRES.

Specication of Letters Patent. Patented Nov.' 15, 1910.

Application led January 14, 1909. Serial No. 472,167.

To all 'whom 'it may concern:

Be it known that I, STEPHEN G. MARTIN, a citizen of the United States, and resident -of Chicago, Illinois, have invented certain new and useful Improvements in Processes of Extracting Iron from Its Orcs, of which the following is a specification containing a full, clear, and exact` description, reference being had to the accompanying drawings, forming a part hereof.

My "nvention relates to a process of cxtractmg 1ron from its ores and 1ts subsequent the Bessemer blow.

The desirable qualities in iron applicable for the manufacture of steel are those of a metal free, or practically free, from sulfur, silicon, phosphorus and the like, and, it; is well known that such metalloids remain in undesirable quantities in iron produced by ordinary processes in -blast furnaces.

My invention consists in dispensing with the use of atmospheric air in the blast fur- Anace and substituting therefor' modified or which is to be converted into steel by the' Bessemer process.

It has been demonstrated that when ordinary atmospheric air is passed. through the flame of an electric discharge or through a iaininv arc of electricity, a gaseous medium is produced consisting of pure air and gaseons peroxid of nitrogen, and this is the sens'.A in which applicant uses the expression modified or' ionized -air the gaseous peroxid of nitrogen being the active agent in furnace as rapidly as it is formed. Under these conditions dissociation of the as (the temperature of the furnace beino taken into consideration) does not take place during its passage from its source of supply to the furnace. It is, therefore, not necessary that .means be provided to insure stability of the gas.

In the drawing I have shown an ordinary blast furnace equipped for the carryingA out of my improved process, and referrmg by numerals to said drawing, 1 designates the which leads one or more pipes 2, and located. 1n these pipes are. housln s 3, 1n. each of erly connected to an electric generator an adapted yto produce a liaming .electric discharge. The portions of the plpes Q, leading to these housings 3, .are preferably connected to blast fans, or like means of forcing atmospheric air into thehousings 3.',

In carrying out my improved recess', the iron ore, uxmg material and fue are placed in the furnace 1n the usual manner and after said furnace is fired atmospheric air 1s forced into and through the housings' 3, and as said air passes through the Haming electric discharge between the electrodesfl, sald a1r becomes modified or ionized, and 1n such condition is forced into the furnace and passed upward through the charge thereln.

The principal impurities which I desire to remove are the sulfur and. phosphorus. These impurities are removed partlally by way of the slag or furnace cinders and the stack. The slag and the metal are removed in the ordinary way, through tap holes.

The reactions through'which the sulfur which is located a. pair of e ectrodes 4, prop J70 the process. This gas is conducted into the body of the furnace, into the lower end of ably as follows:

In this reaction, it is understood that moisture (H2O) is present in the upper levels of the furnace. i

The probable reactions which occur in the reduction of the metal from the ore, from.

the beginning of the operation to the formation of the spongy iron, are as follows:

In the piesent methods, the atmosphere within the. furnace, that is to say, in the space above the twyers to thepoint where the temperatuie is about 800 C., consists almost entirely of n-itrogen and carbonio oxid, and one of the objects of my process is secured by adding to the components of said atmosphere gaseous peroxid of nitrogen, thus changing the atmosphere to an atmosphere consisting of carboniol oxid, nitrogen peroxid and nitrogen, and it is apparent that a sensible reduction of the volume of nitrogen conducted into the furnace must furnish a proportionately less amount of this inert gas to absorb and carry out of the furnace (with the exception of the relatively small amount restored to the upper levels) the heat so badly needed in the -operation of reducing the furnace charge, especially in the zone of fusion.

Without assuming to accurately equate all the conditionswliich are brought about during the operation .of reducing iron ore in an atmosphere of nitrogen peroxid, carbonio oxld, carbon dioxid, nitrogen, and the ases usually reckoned as nitrogen, it is believed that the reactions heretofore set forth probably occur. f

I have demonstrated in practice that this modified or ionized airvery rapidly reduces the charge within the furnace and the resultant product is homogeneous and with tracas but a very small per cent. of metalloid impurities.

In ordinary blast furnace pig-iron a por-l tion of the impurities is derived from the iiuxing material and fuel employed iu the reducing operation, but where modified or ionized air is employed inA reducing the charge these impurities are almost entirely eliminated, which result is not attained where atmospheric air is employed in the blast.

I do not desire to limit or confine myself to the use of modified or ionized air produced by passing atmospheric air through the iiame of electric discharge, but under certain conditions satisfactory results may be obtained by utilizing a mixture consisting of atmospheric air and the gaseous products resulting from the action of nitric acid or its compounds upon ferrous sulfate, or it may be found desirable to enrich the modified or ionized air with the nitrogenous oxids produced by the chemical action above stated.

According to the modern blast furnace practice, the blast consists of about 23 parts oxygen and 77 parts nitrogen. This nitrogen gas is practically stable and inert chemically, and .performs no function other than to rob the snielting zone of a large portion of its heat. Now while it is true that a smallportion of this heat is restored to the furnace in its higher levels during the upward passage of the nitrogen, the greater portion of it is carried out at the top of the furnace, and consequently is a total loss to the furnace. 'The special object of my c process is to change this inert and deterring character of the nitrogen content of the blast and render'. it of specific value and use in the process o f ore smelting. This is accomplished by injecting into the blast the gaseous medium heretofore described, namely, peroxid of nitrogen, a gas known to possess in a great degree the property of supporting combustion. In other words, the unstable and inert nitrogen ofthe atmosphere is converted into nitrogenk eroxid before it is sent iii as a part of the last.

I claim:

1. The herein described process of smelting, which consists in converting a portion of the nitrogen of the air into nitrogen peroxid gas -and reducing the ore by heat in the presence of` said nitrogen dperoxid gas.

2. The herein-describe process of smelting ores, which comprises the step of passing into the furnace containing the ores a gaseous medium containing peroxid of nitro` en. g 3. The herein described process of smeltin ores in blast furnaces, which consists in su jecting the ore while in process/of decomposition by heat, to the action of a blast containing' peroxid of nitrogen.

@maze 4. A step in processes of smeltng ores in l ing ores, which consists in subjecting the ore blast furnaces, .which step consists1 in heati while it is being decoxnposed by heat to u ing the ore and subjecting the ore whilehot i gaseous medium containing peroxld of mtroto the action of a gaseousmedium, consistgen. 15 5 lng of pure zur and lutrogen peroxld. In testimony whereof, I have slgned my The herein described process of smeltname to this specification, in presence of 111g ores which conslsts in sub]ect1ng a mlxtwo subscrlblng witnesses.

ture of fluxed ores to the action of heat and STEPHEN G. MARTIN. y a gaseous medium consisting of pure air and. Witnesses: 10 nitrogen eroxid. M. P. SMITH,

6. The herein described process of smelt- E. L. WALLACE. 

